1. Field of the Invention
The present invention generally relates to chip cards of reduced size, such as the cards used in mobile phones or similar hand-held devices incorporating a chip card, like subscriber's identification cards (SIMs) used in combination with known GSM mobile phones.
2. Background Art
Most of recent mobile phones typically make use of so-called “plug-in” cards of ID-000 format as defined by ISO 7816-1 standard. The ID-000 plug-in card has a size of 25×15 mm, with a right hand corner cut off at an angle of 45° in order to facilitate the correct insertion of the card into the card reader. Correct insertion enables safe positioning of the contacts of the card with respect to the corresponding contacts of the reader of the device to which the card is coupled, for instance with respect to the contact pins of the connector or recess housing the card when such device is a mobile phone.
The plug-in card of reduced size was initially introduced to put less constraints on the design of hand-held devices for which there is no need to frequently insert and remove the subscriber's identification card.
However, due to the trend in smaller size and more compact design for present and future hand-held devices, there remains less and less available space inside the device to house the subscriber's identification card, even if the latter is in the “plug-in” ID-000 format.
There has accordingly be a recent need for a chip card of a still more reduced size, to be used in new generation hand-held devices such as mobile phones, PDAs and like miniaturized devices.
A chip card is made from a chip module supporting a chip on its backside and contact areas on its frontside, said module being embedded in a plastic body for making up the final chip card. Since it appears difficult to reduce the size of the chip module (which would involve a complete modification of the module design and of the manufacturing lines), the only possibility to reduce the size of the card essentially lies in a reduction of the size of the card body, to a dimension which is just a few tens of millimetres larger than the size of the module.
Such a reduction in size is technically possible, however there remains the problem of the correct positioning of the card in the receiving device in which it is inserted. In plug-in cards according to ID-000 standard, there is enough area around the module to provide a card with a positioning feature in the form of a cut-off corner, however if the remaining area around the module is typically less than 1 mm, provision of a cut-off corner is virtually impossible given manufacturing tolerances. There is also the fact that a chip card is generally provided with rounded corners, which make almost impossible for the user to differentiate between a rounded corner from a cut-off corner if the latter is not large enough.